Corruption is still king in Afghanistan, according to a new United Nations report released Thursday, which found over half of all Afghan citizens had paid a bribe to a public official in 2012, paying out over $3.9 billion.

The 40 percent spike in bribes from 2009 highlights a government struggling to battle insurgents — and themselves.

According to the report, in most cases, bribes are paid in order to obtain better or faster services, while others are meant to influence police and judicial decisions. In bribes to Afghan National Police, the study found 24 percent of bribes were used to get suspects released.

The data also showed that for every five Afghans who paid at least one bribe in the past year, there was at least one who refused to do so. Perhaps most damaging however, is that it's not due to integrity — it's because they didn't have enough money.

Survey respondents considered corruption in the country to be the number-two problem, right behind security, but words are no match for what's become an embedded social practice. 68 percent of citizens found it acceptable to pay off a civil servant, and in 2012, 59 percent actually did so.

The UN surveyed a representative sample of 6,700 Afghan citizens aged 18 and above across Afghanistan. Of the respondents, 42 percent were women.